I asked on Smogon and here's what I got as a response:
BP teams are fairly hit or miss, some mu's it just autowins but others like Taunt Yveltal or a well played dynamax can just end it. That said there's still a lot of good BP options for full pass teams. I don't think it needs ingrain but it definitely helps, so Bellosom would be the best user of that. I've used bp in tours here with these 6 mons being really solid on BP in general, but other options like Bellosom, Unaware Clefable, Xatu, and Vaporeon all exist but I think you need quite a few of the things I have on that team to not lose to calyrex-s, Yveltal, Groudon, etc.
I'd say when making a BP you probably need: Speed boost lead Dubwool Magic Bounce User Fairy for Yveltal off the top of my head those are super important which is why I used scoli / dub / espeon / mag, with the last 2 just shoring up harder mu's like umbreon for Double Team and Calyrex-S check and since it's a ladder team Indeedee covers for Sash Marsh and also is a good wincon. Could probably go like Bellosom or sometime else > indeedee as well, so there's options